Update SPDX license map
Add tox.ini to run tox with various envs (py27,py33,pep8,pep257)
Ignore .venv* and .tox
Python-3.3 compatibility (while retaining 2.7 compatibility)
Bump version to 0.4.5
Use context manager to read README.rst
Enhance README.rst and fix rST
Reorganize modules.

The core parts of py2pack.py2pack was moved to py2pack while
ProxiedTransport went into py2pack.proxy. This simplifies relative
imports and is much more sane.
Python-3 compat for file_template_list()
Add classifier for Python-3.3
Move tests dir to test (standard location)
Increase test coverage
Ignore coverage and nosetests.xml
Enhance tox.ini
Align flake8 env with pep8
Fix PEP-8 issues